Benign prostatic hyperplasia, or BPH, refers to the benign enlargement of the prostate gland, which usually occurs as a male ages. It is very common, and sometimes is also referred to as benign prostatic hypertrophy or simply an enlarged prostate.
The prostate gland surrounds the urethra and is located between the bladder and the penis. As the prostate enlarges with age, it can result in a narrowing or blockage of the urethra. This can cause more frequent urination, as well as other changes or problems if urine is retained in the bladder. Retention of urine within the bladder can strain the bladder, lead to urinary tract infections, bladder and/or kidney damage, bladder stones and, potentially, incontinence. Severe BPH can result in even more serious conditions.
There are a limited number of surgical treatments at the present time for BPH. One treatment is referred to as transurethral resection of the prostate (TURP), in which a resectoscope is inserted through the penis into the urethra. The resectoscope employs an electrically charged wire loop to cut and remove obstructing prostate tissue.
More recently, laser surgery techniques have been used, which employ a side-firing laser to vaporize the obstructing prosthetic tissue. Although laser surgery results in relatively little blood loss as compared to TURP, it is difficult to control and the long term effectiveness is not known, as tissue regrowth may occur.
There is also a procedure sometimes referred to a transurethral needle ablation (TUNA). This procedure involves cystoscopically placing needles into the prostate and using low-level radio frequency (‘RF”) energy to create selective lesions that are later reabsorbed. Another procedure for treating BPH employs transurethral microwave procedures to heat selected portions of the prostate that are later reabsorbed.
Despite the efforts to provide improved alternative surgical techniques and apparatus, at the present time TURP is often the surgical procedure of choice. Notwithstanding drawbacks with TURP, including the necessity for anesthesia and significant morbidities such as blood loss (with the need for transfusions), incontinence and retrograde ejaculation, it provides relatively long-lasting flow improvement. Compared to the other available procedures, TURP is still considered by some to be the “gold standard” against which other procedures are compared. Accordingly, there continues to be a need for development of new apparatus and methods for treating BPH.
Patents describing microwave, bipolar ablation and other techniques for treating BPH, including attempted creation of a biological stent, include U.S. Pat. Nos. 5,992,419; 5,330,518; 5,509,929, 5,234,004, and 6,638,275. Description of related devices or methods is also found in Chapter 4 of “New Frontiers in Medical Device Technology,” 1995, entitled “Localized Heating of Deep-Seated Tissues using Microwave Balloon Catheters” by F. Sterzer.